Rope-operated mechanism for control drums



R. B. HUNTER ETAL June 6, 1944,

- ROPE-OPERATED MECHANISM FOR common mums Filed July so 1942 2 Sheets-Sheet 1 J1me 1944. R. B. HUNTER 'ETAL 2,350,613

ROPE-OPERATED MECHANISM FOR CONTIZOL DRUMS Filed July 30,,1942 2 Sheets-Sheet 2 Patented June 6, 1944 ROPE-OPERATED MECHANISM FOR CONTROL DRUMS Richard B. Hunter, Shorewood, and Harold L.

Mekelburg, Milwaukee, Wis.,

assignors to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application July 30, 1942, Serial No. 452,936

8 Claims.

This invention relates to an improved ropeoperated mechanism for control drums. I

It is frequently necessary to install drum controllers for electric motors in places which are not readily accessible to the operator. In electric crane installations, for instance, the drum is usually installed near the motor above the operators position. The drums employed in such cases are usually 01 the reversing type, having a central position and a number of speed points on each side of the off position, and are biased to the off position by-a centering spring the bias oi which has to be overcome by force applied manually by the operator, and which spring returns the drum to the off position when the operator releases the operating means of the drum.

Heretofore it has been customary in such installations to attach a rigid or one-piece doubleended lever to the shaft of the drum and to fasten to each end of said lever a rope or the like. By selectively pulling on one or the otherrope the lever and shaft are moved from the off position to the desired operating point, while release of the rope permits the shaft to return to the off position under its normal bias. The use of such a double-ended lever has, however, the limitation that it is unsuitable, as a practical matter, for rotation of the shaft through an angle of more than forty-five degrees on either side of the off position. If a reasonable number of speed points have to be provided for within this angle, the diameter of the rotating cylinder which carries the conventional movable contacts has to be made unduly or unreasonably large to provide for sufi'icient angular spacing between the different speed points.

To overcome the aforementioned disadvantage, it has been proposed to provide such a drum with a sheave wheel and to wind two ropes in opposite directions around the circumference of the wheel. This makes it possible to increase the angular throw of the shaft on each side of the off position and thus permits a decrease in size or diameter of the contact cylinder of the drum. However, the rope has a tendency to jump off the sheave wheel and thus render the drum inoperative. To avoid this a guard which closely surrounds the upper half of the sheave wheel so as to just leave sufiicient space for the rope may be employed. However, such a guard leads to another difiiculty; namely, that the rope may become jammed between the guard and the wheel. If, on the other hand, the clearance between the guard and the wheel is sufficient to-prevent such jamming, the rope may jump off the wheel in the same manner as in the absence of a guard.

The present invention has for its object to provide an operating mechanism which combines the advantages of the one-piece double-ended lever and of the sheave wheel, without the disadvantages of either. The invention resides in providing a pivot member such as a lever having a pair of arms or links pivoted or articulated with respect thereto, said arms being respectively adapted, when operated, to effect rotation of the, drum controller in one direction or the other; an

operating rope being attached to the free end of each of said arms. The articulation of the arms with respect to the lever is such that the drum shaft may be rotated through an angle up to at least one hundred degrees in either direction from neutral or off position thereof, thus providing for a relatively much larger number of speed points than would be possible with a rigid or one-piece double-ended lever, for the same drum diameter. 7

Another objectof the invention is to provide a relatively simple drum operating mechanism affording large total angular movement of the operating shaft. v

Another object is to provide an improveddrum operating mechanism which is sturdy in construction and which is reliable in operation.

Another object is to provide a drum operating mechanism of the aforementioned character which is easily installed and maintained.

Another object is to provide such a drum operating mechanism which is composedof a relatively small number of moving parts.

Another object is to minimize the space requirements of an operating mechanism having the characteristics herein contemplated. n

Other objects and advantages of the invention will hereinafter appear. V i v The accompanying drawings illustrate several embodiments of the invention. v

In the drawings, Figure 1 is an end view of a drum provided with a, rope-operated mechanism constructed'in accordance with our invention;

Fig. 2 is a fragrnentary top plan view of the structure showninFigJ. 7 7 V N Fig 3 shows ;a;forrn of stop or anti-plug e h n r ichim yrbe; em oyed in conjuncs ion wit the on r 'dr m.

Fig;- 4 is a diagrammatic characteristicsofZaQconventional form of ropeoperated, rigid double-ended lever for association wi ha Qm mmrum:

of a modified ,iormlof Fig; 5 is. an end .view:

I illustration of rope-operated "mechanism adapted to perform the same functions as the device illustrated in Figs. 1 and 2 Fig. 6 is a fragmentary side 'elevational view of the device shown in Fig. 5, and

Fig. '7 is a diagram of the electrical connectionsof a drum controller suitable for operation by the mechanism which forms the subject matter of the present invention.

Referring. to Figs. 1 and 2, the numeral I desig- I nates the housing of a drum controller. The

controller is provided with a conventional rotary operating shaft having a square end 2, which in the reverse direction is obvious from the foregoing.

extends beyond one of the end walls'of the casing Y Y I. Mounted on the shaft extension 2, is a metal member 3, shown as a casting, provided with a square hole 4 adapted to receive the extension 2. The casting is slotted at 5, theplane of the slot extending through the central axis of the hole 4,

and dividing one end of the castin into two arms uss; 6 d i 1-; A ca sc ew s s, ree y through a hole 9 inthe' 111g}, and threadedly en gages the lug 6 in such a manner that the screw 8 pullsthelugs 6 and 'I' together to clampthe casth1g3 to the shaft extension 2. v 7 I 4 The casting 3 projects upwardly, the upper end thereof being enlarged laterally and shaped or recessedto form pairs of ears IE3 and I I. Between the earsof each pair is pivotally mounted or articulated a lever I2, the pins for pivotally attachinglevers [2 to ears Ill and II being designated by numerals I3, I3 The free ends of the respective levers I2 ar provided with perforated ears 1,. M, to which may be fastened an operating rope I5. The 'twoipivots I 3 are arranged symmetrically with respect'to the casting 3, and in the normal position of the drum they are positioned symmetrically'with respect to thevertical central plane of thedrum c'on't'roller. Thepivotal inove ment of the levers I 2 towards the shaft 2 is limited by abutm'erl'ts I6 in the throats between the ears of each pair'Ill and II. v

Figs. 1 and. 2 show the drum in th' 'neutral position; Tooperate thedrumthe operator pulls one of tlie'rope's I5, depending upon the direction in which he wishes to rotate the "drum. If the right-hand rope I5 is pulled, the drum is rotated in a clofikwise direction; whereby the right-hand pivot l3 describes a circl concentric with the shaft 2,;and the right-hand ear I4 at first moves ona similar concentric circle. The one component of theipull on the ear I' l. tends to rotate said lever I2 about said pivot;I3 in a clockwise direction, but such rotation is prevented by the abutment I6, until the ear I4 is at'a point which is vertically below th position of the pin I3. Further rotation of the shaft'by the'pull on the rope l5 produces a component on the lever I2 which rotates it in a counterclockwise direction relative to the pivot I 3, so that as'shown in dotted lines the center of the ear I4 and the pivot I3 are always in the same vertical plane and in alinement with the ropeI5.

Y During the first movement of the drum the torque acting on the shaft 2 operates on a leverage which is equal to the central distance of the ear I4 from the vertical central planethrough the drum shaft, as th drum rotatesfromthe center position this leverage decreases'u'ntil the center of the ear ['4 is vertically below the pivot I3. Thereafter the leverage increases-as the pivot I3 moves towards the point-of intersection between a-horizontal planethrough the' sh'aft 2, and the radius ofth'e'pivot I3 at the point A. Further rotation of the shaft causes the leverage todecrease again until the position indicated by dotted A comparison of Fig. l with Fig. 4 shows the marked improvement in the operation of the pres- -entstructure over the conventional double-ended lever.

In Fig. ithe numeral 20 designates a conventional double-ended lever attached to the shaft 2. It will be noted that for the same variation in leverage th drum can only be operated through an angle of approximately forty-five degrees in either direction from the horizontal or neutral position, whereasinthe structure shown in Figs. 1 and 2, the angle of operationfromneutral position in either direction is approximately one hundred degrees. Thus it is possible with the present construction to operate a drum of a given diameter having more than twice the number of speed points of a drum of the same diameter when used in conjunction with a conventional doubleended lever of the character illustrated in Fig. 4.

Referring now to the devic of Figs. 5 and 6, the structure comprises a box-shaped support made of two like sheet metal plates 20 and 2I, respectively. The ends 20 and M of the plates are bent at right angles to the main bodies thereof and are assembled to form a closed channel or box. Each plate is provided with two square openings 23, 23 of like size (see Fig. 5), the lower opening 23 of front plate 20 being alined with the opening 23 of the rear plate 2I (see Fig. 6) to freely accommodate the en of the shaft .2. The two plates 20 and 2| are held together by a pair of screws 24, 24 and a second pair of screws 25, 25. Said plates are held at the desired distance from each other by four spacers 26 surrounding the shanks of the pairs of screws 24 and 25. A clamp 21 is provided with a V-shaped bend intermediate its ends to fit one-half of the shaft 2. The clamp 21 is provided with holes 21 2'! near its opposite ends. @Holes 21*, 21 in clamp 21 are adapted to be alined with a pair of openings 28, 28 in flange Zl of the plate 2 I, a similar pair of openings .(not'shown) being provided in flange 20. A pair of bolts 29, 29, respectively pass through the alined openings 28 and holes 21 and are provided with nuts 30, 30 to rigidly secure the assembled plates Ziland 2|; and the clamp 21 to the shaft 2. Levers 3I ar pivotally supported upon the spacers 26 carried by the upper pair ,of screws 25, 25. Each lever 3| preferably comprises a metal rod of circular cross section which is provided with ears 32 and 33,respectively, at its opposite ends. The ears 32, '32 surround the aforementioned spacers 26, 26 to afford such pivotal support for said levers. Washers '34, 34 (see Fig. 6) are interposed between the plates 20 and 2I,-respectively, and'the cars 32, 32. A rope I5 is attached to each of the ears 33.

The rotation of 'the'levers' 3I toward the shaft 2 is limited by the spacers 25 associated with the lower pair of screws Z-Lfas best illustrated in Fig. 5. The spacers 26 thus act as abutment-s for the levers 35 in a manner similar to the abutments lta ofFigml.

he operation-of the device shown in Figs-5 and 6 issimila'r to that'shown in Figs. 1 and '2;

and is not believed to-require;further explanation. In this case also the angular throw obtainable for a given variation in leverage is large and is the same as that of the-device shown in Figs, 1

and 2. y 1

Referring now to Fig; 3the same illustrates an anti-plugging devicerwhich temporarily arrests the operating shaft in the center position under certain conditions A drum controller which is provided with a rope-operatedmechanism such as described heretofore is as previously stated usually provided with a conventional centering. spring or other means whereby after have ingbeen moved to an'operating position the shaft is returned to the neutral position upon release of the operating rope. Inasmuch as the drum cylinder and other rotatingparts have considerable inertia there is a tendency for the drum cylinder to overshoot the neutral: position andto effect closure of a circuit for reverse operation of the motor controlled by the drum. To avoid such a result, it is desirable to provide such a drum with means to insure slow movement of the drum through or temporary arrest thereof in the center or neutral position. 'A device of this general character is disclosed and claimed in our Patent No. 2,307,373, granted January 5, 1943, for Rotary electric" switch. I v p Fig. 3 shows an arrangement which is particularly suited for use in connection with the aforedescribed rope-operated mechanism. Mounted on the shaft 2and rotating therewith is a cam 35. This cam is provided with a slot or recess 36. The controller is provided with a pivot pin 31 preferably fastened to one of the end walls of the casing A double-ended lever 38 is provided on the pivot pin 31. One end of the lever 38 is provided with a lug 39; which upon rotation of the lever in a counterclockwise direction under given conditions enters the recess '36 and thus prevents the drum from being rotated beyond the center or neutral position. The other end of the lever 38 is provided with an extension 40'which' carries an'a'djusting screw 4|. The adjusting screw 4|is arranged to abut cam surfaces 46 and 41 of the cam '35 which limit clockwise rotation of the lever 38. A fiat spring 42 has one end thereof fastened to the lever 38, while the other end abuts against a stationary bracket 43 in such a manner, that the spring tends to rotate the lever in a clockwise direction and to withdraw the lug 39 from the recess 36. The bracket 43 also carries an adjustable stop screw 44, the end of whichis adaptedto engage an abutment 45 on the lever 38, thereby positively limiting the clockwise rotation of the lever 38 independently of the. action of stop screw 4| with respect to either cam surface 46 or 41.

Normally the stop screw 4| follows one of the two cam surfaces 46 or 41, respectively, as the shaft 2 is rotated from the center position in either direction. As the radius of the point of abutment between the stop screw 4| and the cam surfaces 46 and 41 decreases upon such rotation, the spring 42 causes the lever 38 to rotate clockwise thus further withdrawing the lug 39 from the recess 36 'until the lever is-prevc ented from further rotation by abutment thereof" against the screw 44. Thus the distance by which the lug 39 is withdrawn'from the recess 36 increases with increasing angle of rotation of the shaft 2 from the central position If now the: shaft is released from an operating position and returned by'the centering means towards the center posi-. tion; the cam surface 46 or 41 pushes against the stop screw and rotates the lever 38 in a 'coun'-. terclockwise direction. As this movement is rapid the acceleration of the lever 38 is such that it acquires speed and rotates ahead of the position determined by the cam surfaces 46 and 41 and against the bias of spring 42. Hence when the cam 35 arrives in the center position the lug 39 enters the recess 36 and stops the drum momentarily from over-running the center position. The counterclockwise rotation of the lever 38 is stopped when lug 39 enters the recess 36 and its stored energy is consumed by the impact, whereupon the spring 42 again becomes effective to withdraw the lug 39 and to permit rotation of the drum in either direction by a pull upon one or the other of the ropes l5.

It will be noted that due to the shape of the cam surfaces 46 and 41 the rate of acceleration ofthe lever 38 from any operating position increases with the angle of displacement of the drum cylinder from its neutral position. The speed at which the drum reaches the center position due to the acceleration of the centering spring also increases with increasing angle of rotation from center. Therefore the speed with which the lug 39 tends to enter the recess 36 increases with the tendency of the drum to overrun the center position. Thus it will be apparent that the centering means are particularly suited to and effective in connection with the operating mechanism illustrated herein, which permits the operation of the drum cylinder through a very large angle of rotation. The efficient centering means described affords accurate control of the position of the drum cylinder and effective stoppage thereof in the neutral position upon release of the operating rope.

Referring now to Fig. 7 the same is a diagram of the electrical connections of a drum controller incorporating our invention. In Fig. 7 the reference characters L L and L designate the supply lines of a three-phase power system. The lines L and L are connected to suitable stationary contacts 59 of the drum controller, and certain of the contacts 56 are also connected to the primary winding 5| of a motor 52. The connections between lines L1 and L and the motor winding are reversed by the operation of pairs of revers ing contact segments 54 of the drum controller. The line L is directly connected to the primary winding 5|.

The secondary winding 55 of the motor 52 is connected to stationary contacts 56 of the drum controller, which is further provided with sta-' tionary contacts 51 to which are connected three speed regulating resistors 58. Drum contact segments 59 on the movable cylinder of the drum are arranged to commutate the resistors in a conventional manner, so as to vary the resistance in the secondary circuit of the motor to thereby provide a number of different speeds for the motor. It will be noted that with the arrangement shown the drum controller provides for five speeds in either direction, corresponding to a total of ten speed points for rotation of the drum cylinder from one extreme operating position to the opposite extreme position.

It is obvious that between any two adjacent operating positions and between the first operating position and the neutral position there must be a given minimum angular movement so as to separate the various operating points from each other. As the drum controller with the improved operating mechanism shown herein provides for an angular movement of approximately one hundred degrees in each direction from neutral position, the angular movement fromone position to the next is approximately twenty degrees, which is sufficient to provide for handling of cur-- rents of considerable magnitude and voltage. With the conventional rope-operated drive providing only forty-five degrees maximum rotation in either direction, only two or three positions in each direction are obtainable, unless the angular movement from one position to the next is decreased, which would require a corresponding increase of the diameter of the drum cylinder to afford the same linear or circumferential dis tance between contact points for a given current and voltage to be handled.

It will be obvious to those skilled in the art that the device of Figs. 1 and 2 may be modified byfmaking use of two or more links, such as I2, for each direction of operatiomwith proper abutmer ts thereon to limit the pivotal movement therebetween in one direction, whereby the structureis adapted to angular movements of the drum shaft greater than one hundred degrees from the off position. Where the angular movement exceeds approximately one hundred degrees such groups of links will, of course, preferably be arranged in parallel planes.

In a similar manner, the device of Figs. land 2 may be modified by extending the pairs of ears in and H (with integral connecting portions therebetween, corresponding to extensions of the abutments IS) in the form of arcs corresponding in curvature and length to those of levers l2, and to attach by pins like or similar to pins !3 one end of each of a pair of sprocket type chains or similar members characterized by pivoting or articulation of their multiple sections or elements, and further characterized by movability of said sections relatively to each other only in a single plane. Such an arrangement has the advantage that the lengths of sprocket chain would be automatically retained in alinement with the grooves thus formed in the extensions of member 3 in the event of either manual or automatic movement of the latter, and would effectively resist manual movement of the chain sections out of their normal plane in the event of an improper angle of pull upon the rope or similar element attached to the lower end of each chain. The grooves in which such lengths of sprocket chain are adapted to seat may be provided with relatively high side walls-converging toward the bottom walls of the grooves to accentuate the finding or aliningcharacteristics of the chain lengths with respect thereto. Various other modifications of the forms of our. invention herein illustrated will at oncesuggest' themselves to those skilled in the art. i

From the foregoing it is apparent that in ac-I cordance with our invention a drum controller is provided which, for a given capacity and for a given number of speeds, is much more compact and can be operated with greater facility-- while affording a more positive or more perfect control of the speed of a motor-than is possible with the rope-operated drum controllers heretofore employed.

1. A rope-operated lever adapted, for rigid attachment to the horizontally 'positioned- 'rota table shaft of a drum controller, said shaft being biased to a given rotary ofi" position wherein the central radius of said lever extends in a substantially vertical. plane in line with the axis of said shaft, said lever having attached thereto a pair of link members articulated in the plane of rotation'of said lever and arranged symmetrically withrespect to saidfvertical plane, the free ends of said link members being spaced a substantial distance from said vertical plane when the shaft'is in off position,- and individual operating members attached 'to the free ends of said link'members and depending therefrom respectively, each of said operating members when subjected to a substantially vertical downward pull acting through its respective link member upon said lever to effect rotary movement of said shaft from its fofi? position through an angular range of the order of one hundred degrees in one directionor the other from said ofPposition.

2: A-rope-operatedlev'er adapted for rigid attachment to the horizontally positioned rotatable shaft of a drum controller, said shaft being biased to a given rotary ,off" position wherein the cen'tral'radius of said lever extends in a substantially vertical plane in line with the axis of said shaft, said lever having attached thereto a pair of links articulated in the plane of rotation of said lever and'arranged symmetrically with respect to said vertical plane, the free ends,

of said links being spaced a substantial distance from said vertical plane when the shaft is in off position, individual'operating members attached to the free ends of said links and depending therefrom'respectively, each of said operating members when subjected to a substantially vertical downward pull acting through its respective link upon said lever to effect rotary movement of said shaft from its off position through an angular range of the order of one hundred degrees in one direction or the other from said off. position, and means to insure temporary arrest of the movement of said shaft in the off position upon manual release of either of said members when said shaft is in other than said off position.

3. A rope-operated lever adapted for rigid attachment to the horizontally positioned rotatable shaft of a drum controller, said shaft being biased to a given rotary o position wherein the central radius of said lever extends in a substantially vertical plane in line with the axis of said shaft, said lever having a pair of arms articulated in the plane of rotation of said lever and normally positioned symmetrically with respect to said vertical plane, the free ends of said arms being spaced from said vertical plane and positioned below a horizontal plane in line with, the shaft when in its oif" position, and individual operating members attached to the free ends of said arms and depending therefrom respectively, each of said operating members when subjected to a substantially vertical downward pull acting through its respectively associated arm upon said lever to effect rotary movement of said shaft through an angular range of the order of one hundred degrees in one direction or the other from the off position of said shaft.

1 4. A rope-operated lever adapted for rigid attachment to the horizontally positioned rotatable shaft of a drum controller, said shaft being biased to a given rotary off position wherein the central radius of said lever extends in a substantially verticalplane in line with the axis of said shaft, said lever having a pair of members articulated in the plane of rotation of said lever and normally positioned symmetrically with respect to said vertical plane, the free ends of said articulated members being spaced from said vertical plane and positioned below a horizontal plane in line with the shaft when in its off position, and individual operating members attached to the free ends of said articulated members and depending therefrom respectively, each of said operating members when subjected to a substantially vertical downward pull acting through its respectively associated articulated member upon said lever to effect rotary movement of said shaft through an angular range of the order of one hundred degrees in one direction or the other from the off position of said shaft, whereby the force required to effect initial rotary movement of said shaft in either direction is minimized.

5. A rope-operated lever adapted for rigid attachment to the horizontally positioned rotatable shaft of a drum controller, said shaft being biased to a given rotary off position wherein the central radius of said lever extends in a substantially vertical plane in line with the axis of said shaft, said lever having a pair of arms articulated in the plane of rotation of said lever and arranged symmetrically with respect to said vertical plane, the free ends of said arms being spaced from said vertical plane and positioned below a horizontal plane in line with the shaft when in its position, individual operating members attached to the free ends of said arms and depending therefrom respectively, each of said operating members when subjected to a substantially vertical downward pull acting through its respectively associated arm upon said lever to effect rotary movement of said shaft through an angular range of the order of one hundred degrees in one direction or the other from the off position of said shaft, and means to temporarily arrest the movement of said shaft in the off position upon release of either of said members from an on position thereof.

6. In combination, a multiple-speed controlling electric drumcontroller having sets of movable contact segments extending along angular ranges of approximately one hundred degrees on each side respectively of an off position, sets of stationary contacts to be engaged thereby, a horizontally positioned rotatable shaft for effecting movement of said sets of contact segments jointly, a lever rigidly attached to said shaft, said shaft being biased to the given rotary off position wherein all of said contact segments are disengaged from said stationary contacts, said lever having attached thereto a member articulated in the plane of rotation of said lever, the free end of said articulated memher being spaced a substantial distance from the vertical plane in line with the axis of said shaft when the shaft is in off position, and an operating member attached to the free end of said articulated member and depending therefrom, said operating member when subjected to a substantially vertical downward pull acting through said articulated member upon said lever to effect rotary movement of said shaft from its off position through an angular range of approximately one hundred degrees.

7. In combination, a multiple-speed controlling drum controller having sets of movable contact segments extending along angular ranges of approximately one hundred degrees on each side respectively of an off position, sets of stationary contacts to be engaged thereby, a horizontally positioned rotatable shaft for effecting movement of said sets of contact segments jointly, a lever rigidly attached to said shaft for movement in a plane at a right angle to the axis of the latter, said lever having attached thereto a member articulated in the plane of rotation of said lever, the free end of said articulated member being spaced laterally a substantial distance from the vertical plane through the axis of said shaft when the shaft is in off position, and an operating member attached to the free end of said articulated member, said operating member when subjected to a manual downward pull at substantially a right angle to the axis of said shaft acting through said articulated member upon said lever to effect rotary movement of said shaft from said off position through an angle of approximately one hundred degrees.

8. In combination, a reversing and multiplespeed controlling drum controller having sets of movable contact segments extending along angular ranges of approximately one hundred degrees on each side respectively of an intermediate o position, sets of stationary contacts to be engaged thereby, a horizontally positioned rotatable shaft for effecting movement of said sets of contact segments jointly, said shaft being biased to the intermediate rotary off position wherein all of said contact segments are disengaged from said stationary contacts, a lever rigidly attached to said shaft for movement in a plane at a right angle to the axis of the latter, said lever having attached thereto a pair of members, each of said members being articulated in a plane parallel to the plane of rotation of said lever, th free ends of said articulated members being spaced laterally like substantial distances from the vertical plane through the axis of said shaft when the shaft is in off position, and individual operating members attached to the free ends of said articulated members, each of said operating memhere when selectively subjected to a manual downward pull at substantially a right angle to the axis of said shaft acting through its associated articulated member upon said lever to effect rotary movement of said shaft from its off position through an angular range of approximately one hundred degrees.

RICHARD B. HUNTER. HAROLD L. MEKELBURG. 

